﻿<%@ WebHandler Language="C#" Class="GenericHandler" %>

using System;
using System.Web;
using System.IO;
using System.Drawing;
using System.Collections.Generic;
using System.Web.SessionState;

public class GenericHandler : IHttpHandler, IRequiresSessionState
{
    public void ProcessRequest(HttpContext context)
    {
        string f = context.Request.QueryString.Get("f");
        string s = context.Request.QueryString.Get("s");
        if (!string.IsNullOrEmpty(f))
        {
            HttpPostedFile file = context.Request.Files[f];
            if (file == null)
                HttpContext.Current.ApplicationInstance.CompleteRequest();
            else
            {
                List<string> keys = new List<string>();
                foreach (string key in context.Session.Keys) if (key.StartsWith(f)) keys.Add(key);
                foreach (string key in keys) context.Session.Remove(key);
                System.Drawing.Image image = Bitmap.FromStream(file.InputStream);
                context.Session[f + "image"] = image;
                context.Session[f + "contextType"] = context.Request.Files[0].ContentType;
                context.Response.Flush();
                HttpContext.Current.ApplicationInstance.CompleteRequest();
            }
        }
        else if (!string.IsNullOrEmpty(s))
        {
            string ck = s + "contextType";
            string ik = s + "image";
            if (context.Session[ck] == null || context.Session[ik] == null)
            {
                HttpContext.Current.ApplicationInstance.CompleteRequest();
                if (context.Session[ck] != null) context.Session.Remove(ck);
                if (context.Session[ik] != null) context.Session.Remove(ik);
            }
            else
            {
                using (System.Drawing.Image image = (System.Drawing.Image)context.Session[ik])
                {
                    context.Response.Clear();
                    context.Response.ClearHeaders();
                    string type = context.Session[ck].ToString().ToLower();
                    System.Drawing.Imaging.ImageFormat format = System.Drawing.Imaging.ImageFormat.Gif;
                    bool isValid = true;
                    if (type.Contains("bmp")) format = System.Drawing.Imaging.ImageFormat.Bmp;
                    else if (type.Contains("jpg") || type.Contains("jpeg")) format = System.Drawing.Imaging.ImageFormat.Jpeg;
                    else if (type.Contains("png")) format = System.Drawing.Imaging.ImageFormat.Png;
                    else if (type.Contains("gif")) format = System.Drawing.Imaging.ImageFormat.Gif;
                    else if (type.Contains("wmf")) format = System.Drawing.Imaging.ImageFormat.Wmf;
                    else if (type.Contains("tiff") || type.Contains("tif")) format = System.Drawing.Imaging.ImageFormat.Tiff;
                    else if (type.Contains("exif")) format = System.Drawing.Imaging.ImageFormat.Exif;
                    else isValid = false;
                    if (isValid)
                    {
                        using (MemoryStream stream = new MemoryStream())
                        {
                            image.Save(stream, format);
                            context.Response.BinaryWrite(stream.ToArray());
                            context.Response.ContentType = type;
                        }
                    }
                    context.Session.Remove(ck);
                    context.Session.Remove(ik);
                    HttpContext.Current.ApplicationInstance.CompleteRequest();
                }
            }
        }
    }
 
    public bool IsReusable {
        get {
            return false;
        }
    }
}